This invention generally relates to peripheral devices for use with computers and similar information processing devices.
A computer keyboard is a peripheral modeled after the typewriter keyboard. Keyboards are used to input text and characters into the computer and to control the operation of the computer. Physically, computer keyboards are an arrangement of rectangular or near-rectangular buttons or “keys,” which typically have engraved or printed characters. In most cases, each depressing of a key corresponds to a single symbol. However, some symbols require that a user depresses and holds several keys simultaneously, or in sequence. Depressing and holding several keys simultaneously, or in sequence, can also result in a command being issued that affects the operation of the computer, or the keyboard itself.
There are several types of keyboards, usually differentiated by the switch technology employed in their operation. The choice of switch technology affects the keys' responses (i.e., the positive feedback that a key has been depressed) and travel (i.e., the distance needed to push the key to enter a character reliably). One of the most common keyboard types is a “dome-switch” keyboard, which works as follows. When a key is depressed, the key pushes down on a rubber dome sitting beneath the key. The rubber dome collapses, which gives tactile feedback to the user depressing the key, and cause a conductive contact on the underside of the dome to touch a pair of conductive lines on the Printed Circuit Board (PCB) below the dome, thereby closing the switch. A chip in the keyboard emits a scanning signal along the pairs of lines on the PCB to all the keys. When the signal in one pair of lines changes due to the contacting, the chip generates a code corresponding to the key connected to that pair of lines. This code is sent to the computer either through a keyboard cable or over a wireless connection, where it is received and decoded into the appropriate key. The computer then decides what to do on the basis of the key depressed, such as display a character on the screen, or perform some action. Other types of keyboards operate in a similar manner, with the main differences being how the individual key switches work. Some examples of other keyboards include capacitive keyboards, mechanical-switch keyboards, Hall-effect keyboards, membrane keyboards, roll-up keyboards, and so on.
The most common physical arrangements of keys on keyboards in Western countries are based on the “QWERTY” layout (including closely related variants, such as the French “AZERTY” layout). However, in countries that do not use the Western alphabet, the keyboard layout is often very different. Most computers allow a user can change the keyboard settings, or keyboard locale, for example, from a conventional QWERTY keyboard layout to a keyboard layout for the Cyrillic alphabet. Typically, there is an indication on the computer screen telling the user knows what keyboard locale is currently selected. However, nothing about the physical appearance of the keys themselves changes when a different locale is selected, so there is no way for a user to know what Cyrillic character will appear on the screen when a particular English key is depressed, unless the user has already memorized the locations of all the Cyrillic characters on the keyboard.
Furthermore, many software applications makes extensive use of the various function keys on a computer keyboard, as well as the “Ctrl” and “Alt” keys, and various combinations thereof with the alphanumeric keys on the keyboard. It is often difficult for a user to remember what operations the various function keys perform in different software applications, and what effect depressing a “Ctrl” or “Alt” key in combination with an alphanumeric character will have in various software applications. Therefore, in view of the above discussion, there is a need for a better way to indicate to a user what the effect will be of depressing a particular key or combination of keys on a peripheral device, such as a keyboard.